It's probably only releasing the memory for RbArray and not what it refers to.
m_objects is a dynamic array, and so it's memory is elsewhere on the heap
rather than being part of RbArray itself. So, it probably doesn't get released
when the RbArray is deleted.

Is it a bug?

Even if it were, it wouldn't get fixed. delete is being removed from the
language. You really shouldn't be using it.
- Jonathan M Davis